EP 0217498 B1 19900912 - HARDENABLE CAST IRON
Title (en)
HARDENABLE CAST IRON
Publication
Application
Priority
US 77281885 A 19850905
Abstract (en)
[origin: EP0217498A1] A method is disclosed for forming a surface hardenable cast iron article by development of metastable retained austenite in the cell boundary of a ductile or semiductile cast iron. The method comprises (a) controlling the solidification of a cast iron melt to extend the eutectic arrest time to 4-12 minutes, the melt having by weight percent a carbon equivalent (carbon plus one-third silicon) equal to 4.3-5.0, manganese .55-1.2, nickel .5-3.0, and the remainder essentially iron, the melt having been treated to form cell boundaries in the solidified iron with a high proportion of the manganese being segregated in the cell boundaries; (b) subjecting the solidified cast iron to an austempering heat treatment to permit the segregated manganese in the cell boundaries to form metastable retained austenite; and (c) terminating the heat treatment prior to the conversion of the metastable austenite to a stable microstructure. To obtain the benefits of wear resistance, the method further comprises using the heat treated cast iron by stressing a surface region thereof and transforming the microstructure of such surface region to martensite.
IPC 1-7
IPC 8 full level
C21C 1/10 (2006.01); C21D 5/00 (2006.01); C21D 7/04 (2006.01); C22C 37/04 (2006.01)
CPC (source: EP US)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0217498 A1 19870408; EP 0217498 B1 19900912; AU 593837 B2 19900222; AU 6234386 A 19870312; CA 1244323 A 19881108; DE 3674125 D1 19901018; JP S62142743 A 19870626; MX 164056 B 19920713; US 4666533 A 19870519
DOCDB simple family (application)
EP 86305626 A 19860722; AU 6234386 A 19860904; CA 512731 A 19860627; DE 3674125 T 19860722; JP 18183086 A 19860801; MX 345686 A 19860815; US 77281885 A 19850905